[winlogbeat] Add handling for missing event data types in the experim…

…ental API (#41418) (#41512)

* [winlogbeat] Add handling for missing event data types in the experimental API (#40684)

* Check type assertion result before using the result

* Update CHANGELOG.next.asciidoc

* Use sync.OnceValue to lazy init ansi decoder

* Move cached encoder out of function

* Add comment to clarify default cp

* Update strings_windows.go

(cherry picked from commit 36c3d5d)

Co-authored-by: Marc Guasch <marc-gr@users.noreply.github.com>

CHANGELOG.next.asciidoc

@@ -395,6 +395,8 @@ https://github.com/elastic/beats/compare/v8.8.1\...main[Check the HEAD diff]
 
 *Winlogbeat*
 
+- Add handling for missing `EvtVarType`s in experimental api. {issue}19337[19337] {pull}41418[41418]
+
 
 *Functionbeat*
 

winlogbeat/sys/strings.go

@@ -44,3 +44,27 @@ func RemoveWindowsLineEndings(s string) string {
 	s = strings.Replace(s, "\r\n", "\n", -1)
 	return strings.TrimRight(s, "\n")
 }
+
+// BinaryToString converts a binary field which is encoded in hexadecimal
+// to its string representation. This is equivalent to hex.EncodeToString
+// but its output is in uppercase to be equivalent to the windows
+// XML formatting of this fields.
+func BinaryToString(bin []byte) string {
+	if len(bin) == 0 {
+		return ""
+	}
+
+	const hexTable = "0123456789ABCDEF"
+
+	size := len(bin) * 2
+	buffer := make([]byte, size)
+
+	j := 0
+	for _, v := range bin {
+		buffer[j] = hexTable[v>>4]
+		buffer[j+1] = hexTable[v&0x0f]
+		j += 2
+	}
+
+	return string(buffer)
+}

winlogbeat/sys/strings_test.go

@@ -36,6 +36,12 @@ func TestUTF16BytesToString(t *testing.T) {
 	assert.Equal(t, input, output)
 }
 
+func TestMakeDisplayableBinaryString(t *testing.T) {
+	input := []byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF}
+	output := BinaryToString(input)
+	assert.Equal(t, "0123456789ABCDEF", output)
+}
+
 func BenchmarkUTF16BytesToString(b *testing.B) {
 	utf16Bytes := common.StringToUTF16Bytes("A logon was attempted using explicit credentials.")
 

winlogbeat/sys/strings_windows.go

@@ -0,0 +1,53 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package sys
+
+import (
+	"sync"
+
+	"golang.org/x/sys/windows"
+	"golang.org/x/text/encoding"
+	"golang.org/x/text/encoding/charmap"
+)
+
+var getCachedANSIDecoder = sync.OnceValue(initANSIDecoder)
+
+func initANSIDecoder() *encoding.Decoder {
+	ansiCP := windows.GetACP()
+	for _, enc := range charmap.All {
+		cm, ok := enc.(*charmap.Charmap)
+		if !ok {
+			continue
+		}
+		cmID, _ := cm.ID()
+		if uint32(cmID) != ansiCP {
+			continue
+		}
+		return cm.NewDecoder()
+	}
+	// This should never be reached.
+	// If the ANSI Code Page is not found, we will default to
+	// Windows1252 Code Page, which is default for ANSI in
+	// many regions and corresponds to Western European languages.
+	return charmap.Windows1252.NewDecoder()
+}
+
+func ANSIBytesToString(enc []byte) (string, error) {
+	out, err := getCachedANSIDecoder().Bytes(enc)
+	return string(out), err
+}

winlogbeat/sys/wineventlog/syscall_windows.go

@@ -442,11 +442,16 @@ func (v EvtVariant) Data(buf []byte) (interface{}, error) {
 	switch typ {
 	case EvtVarTypeNull:
 		return nil, nil
-	case EvtVarTypeString:
+	case EvtVarTypeString, EvtVarTypeEvtXml:
 		addr := unsafe.Pointer(&buf[0])
 		offset := v.ValueAsUintPtr() - uintptr(addr)
 		s, err := sys.UTF16BytesToString(buf[offset:])
 		return s, err
+	case EvtVarTypeAnsiString:
+		addr := unsafe.Pointer(&buf[0])
+		offset := v.ValueAsUintPtr() - uintptr(addr)
+		s, err := sys.ANSIBytesToString(buf[offset:])
+		return s, err
 	case EvtVarTypeSByte:
 		return int8(v.ValueAsUint8()), nil
 	case EvtVarTypeByte:
@@ -476,15 +481,28 @@ func (v EvtVariant) Data(buf []byte) (interface{}, error) {
 			return false, nil
 		}
 		return true, nil
+	case EvtVarTypeBinary:
+		addr := unsafe.Pointer(&buf[0])
+		offset := v.ValueAsUintPtr() - uintptr(addr)
+		return sys.BinaryToString(buf[offset:]), nil
 	case EvtVarTypeGuid:
 		addr := unsafe.Pointer(&buf[0])
 		offset := v.ValueAsUintPtr() - uintptr(addr)
 		guid := (*windows.GUID)(unsafe.Pointer(&buf[offset]))
 		copy := *guid
 		return copy, nil
+	case EvtVarTypeSizeT:
+		return v.ValueAsUintPtr(), nil
 	case EvtVarTypeFileTime:
 		ft := (*windows.Filetime)(unsafe.Pointer(&v.Value))
 		return time.Unix(0, ft.Nanoseconds()).UTC(), nil
+	case EvtVarTypeSysTime:
+		st := (*windows.Systemtime)(unsafe.Pointer(&v.Value))
+		var ft windows.Filetime
+		if err := sys.SystemTimeToFileTime(st, &ft); err != nil {
+			return nil, err
+		}
+		return time.Unix(0, ft.Nanoseconds()).UTC(), nil
 	case EvtVarTypeSid:
 		addr := unsafe.Pointer(&buf[0])
 		offset := v.ValueAsUintPtr() - uintptr(addr)

winlogbeat/sys/zsyscall_windows.go

@@ -0,0 +1,40 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package sys
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var (
+	modkernel = windows.NewLazySystemDLL("Kernel32.dll")
+
+	procSystemTimeToFileTime = modkernel.NewProc("SystemTimeToFileTime")
+)
+
+func SystemTimeToFileTime(systemTime *windows.Systemtime, fileTime *windows.Filetime) error {
+	r1, _, err := syscall.SyscallN(procSystemTimeToFileTime.Addr(), uintptr(unsafe.Pointer(systemTime)), uintptr(unsafe.Pointer(fileTime)))
+	if r1 == 0 {
+		return fmt.Errorf("error converting system time to file time: %w", err)
+	}
+	return nil
+}

winlogbeat/sys/zsyscall_windows_test.go

@@ -0,0 +1,42 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package sys
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/sys/windows"
+)
+
+func TestSystemTimeToFileTime(t *testing.T) {
+	ts := time.Date(
+		2024, time.Month(9), 3,
+		0, 0, 0, 0, time.UTC).UnixNano()
+	st := windows.Systemtime{
+		Year:  2024,
+		Month: 9,
+		Day:   3,
+	}
+	var ft windows.Filetime
+	if err := SystemTimeToFileTime(&st, &ft); err != nil {
+		t.Fatal(err)
+	}
+	assert.Equal(t, ts, ft.Nanoseconds())
+}